Mandrel type rivet setting device



Get. 20, 1970 J. F. MULLEN 3,534,581

MANDREL TYPE RIVET SETTING DEVICE Filed Feb. 8, 1968 2 Sheets-Sheet l |=|6.| 42 FIG. Fa. 2

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INVENTOR.

JAMES F. MULLEN ATTORNEYS Oct. 20, 1976 J, F. MULLEN 3,534,581

MANDREL TYPE RIVET SETTING DEVCE JAMES FQ MULLEN BY Iii-Muay. fu/M ATTOR NEYS United States Patent O 3,534,581 MANDREL TYPE RIVET SETTING DEVICE James F. Mullen, Danvers, Mass., assignor to Malco Products, Inc., Minneapolis, Minn., a corporation of Minnesota Filed Feb. 8, 1968, Ser. No. 703,997 Int. Cl. B21d 9/05 U.S. Cl. 72-391 9 Claims ABSTRACT OF THE DISCLOSURE A rotary tool for setting a mandrel type rivet comprises a mandrel pulling unit that applies tension to the mandrel by means of a drive screw. The mandrel pulling unit is engageable with the drive screw by means of a half-nut clutch engaged upon placing the tool over the rivet and pushing the tool against the work, and disengaged when the mandrel pulling unit has moved a sufficient distance to ensure breakage of the mandrel.

BACKGROUND OF THE INVENTION The lield of this invention generally comprises tools for setting mandrel type rivets. This type of rivet has a hollow barrel with a headed mandrel disposed within it. The setting of the rivet is accomplished by pulling the mandrel head into the rivet to distend the diameter of the barrel at one end, the tension on the mandrel being increased until it fails at a weakened section and separates from the rivet. Rivets of this type and a pliers-type tool for setting them manually are described in the patent to Elliott et al. No. 3,154,210, dated Oct. 27, 1964.

Tools of the type described in said patent feature the use of a serrated gripping jaw that is engaged with the mandrel for applying tension to it, together with means for manually advancing the jaw with the mechanical advantage of a combination of levers. The action typically requires the handles to be gripped, closed together and released repeatedly until the mandrel has been pulled to the breaking point. This action is relatively slow, and in some cases it is diicult to obtain proper access to the work because of the size and shape of the setting tool.

In an elfort to provide faster means for setting this type of rivet and to provide easier access to the rivet for this purpose, relatively complex and costly powerdriven equipment, for example, pneumatioally-operated equipment, has been developed. This equipment is not readily portable and is not suitable for some field applications or for occasional use, as in a home Workshop.

SUMMARY OF THE INVENTION The present invention provides a tool that is adapted to be driven by rotary means without the necessity for an elaborate power unit. While the rotary means may be manually operated, the preferred means comprises a relatively small hand-held motor, driven chuck of the type commonly used with other kinds of tools throughout industry as well as in home workshops. This provides adequate power to set a wide variety of rivets of dilering sizes and metals, depending upon the intended use.

This tool provides ready access to the work, is compact in size and enclosed to protect the operator and to ensure proper lubrication and protection of the parts from entry of corrosive or abrasive foreign matter The foregoing advantages are achieved by means of a half-nut clutch arrangement, combined with means for engaging and disengaging the clutch selectively. Engagement is accomplished by placing and pushing the tool against the work surface and disenagement is accomplished as a function of the distance of travel of the rice mandrel pulling unit during rotative operation of the tool.

BRIEF DESCRIPTION OF T-H-E DRAWINGS FIG. l is an elevation in section taken on the principal longitudinal dimension of the tool, showing the positions of the parts after insertion of a rivet and before its placement in a hole in the work piece.

FIG. 2 is an elevation in section, viewed at right angles to the elevation of FIG. l, showing the parts in the same positions as in FIG. l.

FIGS. 3, 4 and 5 are views in section, respectively taken on lines 3--3, 4 4 iand 5 5 of FIG. l.

FIG. 6 is a bottom view showing the work-engaging end of the tool.

FIG. 7 is an elevation in section showing the tool after it has been pushed against the Work and before setting of the rivet has begun.

FIG. 8 is an elevation in section showing the positions of the parts after the rivet has been set and the mandrel broken, but before return of the mandrel pulling unit to the starting position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, the preferred embodiment of the tool is housed within :a cylindrical metal sleeve 12 preferably of steel. It may be gripped in the hand by grasping a knurled metal sleeve 14, preferably of aluminum or some other light metal, which is secured to the sleeve 12 by spacer rings 16- and screws 18. The work end of the sleeve 12 is closed by an end plate 20 secured by screws 22. This plate slidably supports two half-nut actuating pins 24 having their ends permanently secured in la metal work-engaging ring or operator 26, the ring being adapted to lit within an annular groove 28- of corresponding size and shape in the plate 20. Rings 30 secured on the pins 24 limit their outward movement in the direction toward the work.

The parts within the sleeve 12 comprise two main assemblies or units that are mutually engaged or disengaged, depending upon the moment of time in the cycle of operation. One assembly is designated generally as the drive screw assembly 32. The other assembly is designated generally as the mandrel pulling unit 34. The drive screw assembly is mounted within a bushing 36 threaded in the driving end o-f the sleeve 12,. A drive screw 3,8 is rotatably received within this bushing through a suitable lubricating sleeve 40. The screw 38 has a drive spindle 42, preferably with three flat surfaces evenly spaced about its periphery for engagement in the chuck of a suitable small power tool (not shown), such as that in common use for 3s-inch drill and including a pistol grip. Adjacent the spindle 42 there is an integral flange 44 bearing upon the outer race of a ball thrust bearing 46 force-fitted in a recess in the bushing 36. The screw 38 is retained against axial movement by a washer 48 held by a split retainer ring 50. Thus the screw 38 may be driven rotatably within the sleeve 12 but does not move axially in relation to it.

The mandrel pulling assembly 34 comprises two subassemblies, a mandrel clamping unit 52 and a half-nut clutch 54. These sub-assemblies are pivotally linked in the manner of a clevis joint by means of a pin 56. The mandrel clamping unit is housed within a cylindrical sleeve 58 having lateral holes to receive the clevis pin 56. The pin engages one end of a compression spring 60, the other end of which bears upon a member 62 slidable within the sleeve. This latter member has a conically tapered end surface 64 engageable with two inwardly serrated mandrel grippers 66, these lgrippers each being generally semi-cylindrical in shape and having tapered conical lateral surfaces 68 cooperating with a corresponding inner conical surface of the sleeve 58. The grippers also have conical end surfaces 70 engageable with the correspondingly tapered end of a mandrel receiving head 72 threaded in the end plate 20.

A mandrel type rivet 74 comprising a barrel 76 and a headed mandrel 78 may be inserted in the head 72, between the grippers 66 and into a central hole in the slidable member 62. The spring 60 tends to push the grippers 66 toward the work end, but 'when the sleeve 58 is in the position illustrated in FIG. l, the head 72 holds them out of contact with the inserted mandrel. This permits the easy removal of a spent mandrel when the parts return to this position as hereinafter further described. When the sleeve 58 is pulled upwardly by the clevis pin 56, as described below, the grippers 66 are forced against the mandrel by the tapered surfaces 68 and they grip the mandrel tightly enough to permit it to be pulled to its Ibreaking point.

The sleeve 58 is centrally and slidably located within the outer sleeve 12 by a ring 80 welded to the sleeve 58, this ring having two holes through twhich the pins 24 slidably pass.

The half-nut clutch 54 is a sub-assembly also longitudinally slidable 'within the sleeve 12, and as best shown in FIG. 2 it is assembled within two U-shaped yoke members 82 and 84 permanently and rigidly secured together by rivets 86 or alternatively by welding or other permanent means. Preferably, these members are formed of met-al strapping. The member 84 has transverse holes in its legs through which it is connected by the clevis pin 56 to the mandrel clamping unit. A compression return spring 88 bears upon the central portion of the member 82, continually urging the entire mandrel pulling unit 34 in the direction of the work end. At its other end, this spring bears upon a sleeve member 90 abutting the bushing 36.

A pair of half-nuts 92 having partial threads on their inner surfaces are freely tted between and retained by the central portions of the U-shaped members 82 and 84. The half-nuts have laterally extending recesses to receive two compression springs 94 continually tending to disengage the half-nuts from the drive screw 38.

The half-nuts are engaged or disengaged depending upon the positions of two half-nut setting pins or cams 96 secured by screws 98 in a yoke 100 longitudinally slidable in the space between the legs of the U-shaped member 84. Metal bearing rings 102 of elongated shape as shown in FIG. 2 are reecived on the screws 98 and lie ttingly within longitudinally elongate slots 104 in the sleeve 12. 'Each of the pins 96 has a portion of larger diameter and a portion of smaller diameter and a camming shoulder between the larger and smaller portions, either of which may be brought within a hole passing through one of the half-nuts 92. The holes in the halfnuts are slightly larger than the larger diameter of the pins 96, and the dimensions are such that the half-nuts are forced to engage the drive screw 38 when the enlarged diameter is within these holes, but are allowed to disengage from the drive screw when the smaller diameter is within these holes.

The operation of the tool may Ibe understood by referring iirst to FIG. 1, in which the rivet 74 is shown placed within the mandrel clamping unit 52 but the tool has not yet lbeen placed against the surface of the work. As illustrated in FIGS. 7 and 8, the work may comprise two drilled sheets 106 to be secured together by the rivet 74. As shown in FIG. 1, the return spring 88 has pushed the mandrel pulling unit 34 to its limit position toward the work end of the tool. The half-nuts 92 are disengaged from the drive screw. The rings 102 are near the forward ends of the slots 104 in the sleeve 12.

The next step consists in placing the rivet 74 into the hole in the sheets 106 and pushing the work-engaging ring 26 against the sheets to the position shown in FIG. 7. This forces the pins 24 to push upon the pins 96, forcing the enlarged diameters of the latter into the holes in the half-nuts, whereby the latter engage the drive screw 38.

The next step is to turn on the power drive while holding the tool in the illustrated position in relation to the fwork. Ihe drive screw then draws the entire mandrel pulling unit '34 longitudinally away from the work, with tension being applied to the mandrel 78 of the rivet through the grippers 66. This longitudinal movement continues until the half-nuts are disengaged from the drive screw in the following manner.

At iirst, the mandrel pulling unit moves longitudinally with its respective parts in the relative positions shown in FIG. 7. This continues until the ends of the pins 96 abut the sleeve member 90, by which they are then arrested. The other parts of the mandrel pulling unit continue to move longitudinally until the half-nuts become fully aligned with the smaller diameter portions of the pins 96. This allows the compression springs 94 to release the half-nuts Iand to disengage the drive screw from the mandrel pulling unit, allowing the latter to return to its initial position shown in FIGS. 1 and 2 under the force of the return spring 88.

FIG. 8 shows an intermediate position after the pins 96 have engaged the sleeve 90 but before the half-nuts have been disengaged from the drive screw. This is the approximate position of the parts in which the mandrel will have reached its breaking point, and in this position the end of the mandrel within the grippers become detached from the rivet 74. When the tool is later returned to its original position as described above, the end of the spent mandrel may -be easily removed from the tool, and the latter is then ready to set the next rivet.

The longitudinal movement of the mandrel pulling unit required to set a given rivet depends upon t-he relationship of the thickness of the parts to be joined by it in relation to the length of its barrel. This variable is accommodated by designing the tool to have a sufficient travel distance of the mandrel pulling unit before the smaller diameter portions of the pins 96 are fully within the half-nuts.

The above-described tool has demonstrated a capability of developing very substantial tension. In a relatively small size, it is capable of pulling steel rivets of up to three-sixteenths inch diameter, which requires a force of approximately 1900 lbs.

The torque applied to the tool by the power driven can be resisted with the aid of the hand gripping sleeve 14, or if desired the sleeve 12 may be connected to the housing of the power drive by suitable straps or brackets in a conventional manner.

It will be understood that while this invention has been described with reference to a preferred embodiment, various other adaptations and modifications can also be accomplished in the structure and arrangements of the parts without departing from the spirit or scope of the invention.

il claim:

1. A setting tool for mandrel type rivets having, in combination:

a tubular housing,

mandrel pulling means slidable within the housing for clamping and pulling a rivet mandrel and including a half-nut clutch,

a drive screw rotatably supported within the housing and adapted for engagement by the clutch,

and closing means for sequential engagement and disengagement of the clutch, said closing means including cam means movable endwise Within the housing and acting on the half-nut clutch to effect engagement 0f the screw by the clutch and thereby initiate pulling of the mandrel.

2. The combination according to claim 1, in which the closing means include pin means slidable within the housing and having provision for depression by contact with a work surface to engage the clutch.

3. The combination according to claim 1, in which the clutch comprises a plurality of thread-bearing members laterally movable to engage the threads of the drive screw, said members having pins slidable in holes therethrough, the pins having portions of enlarged diameter movable into said holes to move said thread-bearing members to engage the drive screw and portions of reduced diameter movable into said holes to permit movement of said thread-bearing members to disengage the drive screw.

4. The combination according to claim 3, in which the pins are engageable against the housing and depressable upon a predetermined further movement of the clutch to push the portions of reduced diameter into the holes in the thread-bearing members.

5. The combination according to claim 4, in which the closing means include second pin means slidable within the housing and having provlsion for pushing the portions of enlarged diameter into the holes in the thread-bearing members when pushed against a work surface.

6. A setting tool for mandrel type rivets having, in combination a tubular housing,

mandrel pulling means slidable within the housing for clamping and pulling a rivet mandrel and including a half-nut clutch,

a drive screw rotatably supported within the housing and adapted for engagement by the clutch, closing means for sequential engagement and disengagement of the clutch and including a cam means movable with respect to said half-nut clutch to etect engagement of the screw by the clutch, said cam means also being movable with said half-nut clutch rearwardly within the housing and along the screw,

and an operator at the exterior of the housing to be manually moved and extending into the housing to engage and move the cam means with respect to the half-nut clutch whereby to initiate pulling of the mandrel.

7. The setting tool according to claim 6 and said operator being operably disconnected from the cam means as the cam means and half-nut clutch move along the screw within the housing and permitting the operator to remain stationary.

8. The setting tool according to claim 6 and said cam means including portions protruding from said half-nut clutch and engaging the housing to be stopped thereby while the half-nut clutch continues along the screw to effect disengagement between the half-nut clutch and the screw.

9. The setting tool according to claim 6 and said cam means being movable rearwardly with respect to said half-nut clutch to engage the clutch onto the screw, and said half-nut clutch being movable rearwardly with respect to said cam means to disengage the clutch from the screw, the cam means having a portion projecting rearwardly from the half-nut clutch during rearward travel of the half-nut clutch to engage the housing and be stopped thereby while the half-nut clutch continues rearwardly along the screw and along the cam means whereby to effect disengagement of the half-nut clutch from the screw.

References Cited UNITED STATES PATENTS 3,095,106 6/1963 Morrison 72,-391 3,406,556 10/1968 Musser 72-391 3,412,594 ll/l968 Lund 72--391 3,423,986 l/l969 Young 72-391 CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner U.S. Cl. X.R. 72-454 

